Electrical relay



Sept. 29, 1931. a, MISHELEVICH 1,325,238

ELECTRICAL RELAY Filed Feb. 19. 1931 L I-NM HQ ATTORNEY.

Patented Sept. 29, 1931 UNITED STATES PATENT QFFECE BENJAMIN MISIIELEVICH, OF PITTSBURGH, PENNSYLVANIA ASSIGNOR TO THE UNION SWITCH & SIGNAL COMPANY, OF SWISSVALE, PENNSYLVANIA, A. CORPORATION OF PENNSYLVANIA.

ELECTRICAL RELAY Application filed. February 19, 1931. Serial No. 516,935.

. My invention relates to electrical relays of the type involving an armature which oscillates when the relay is energized. One feature of my invention is the provision-of novel and improved means for varying the rate of oscillation of the armature in a relay of this type.

I will describe one form of relay embodying my invention, and will then point out 1@ the novel features thereof in claims.

In'the accompanying drawings, Fig. 1 is a view, partly in elevation and partly di-- agrannnatic, showing one form of relay embodying my invention. Fig. 2 is a View similar to Fig. 1, but showing the relay adjusted for a diiterent rate of operation.

Similar reference characters refer to similar parts in each of the views.

Referring to the drawings, the relay, in the form here shown, comprises a magnetizable core made up of a back strap 1 and three parallel legs 2, 3 and 4:. An armature 5 is pivotally attached at 5 to the free end of the middle leg 3, and is arranged to swing towards one or the other of the outer legs 2 or 4. A winding 7 is provided on leg 2, and another winding 8 is provided on leg 4, and these two windings are supplied with current from a suitable source, which, as here shown, is a battery 9. These windings are connected in series, and the supply of current to the windings is controlled by a contact 6 operated by the armature 5. The polarity of the current supplied to Winding 8 may be reversed by a pole-changer 10. The armature 5 is preferably biased to the position wherein it is shown in the drawings, so that contact 6-6 is closed when the circuit for the windings is open at contact 11. WVhen contact 66 is closed, winding 8 is on short circuit, and when contact 11 becomes cl'osed,current will be supplied to winding 7. When the armature 5 swings to its opposite position, winding7 will be placed on short circuit and current will then be supplied to winding 8.

WVith the parts in the positions in which they are shown in Fig. 1, I will assume that contact 11 becomes closed, so that winding 7 will become energized. The armature 5 will then swing in clockwise direction until its left-hand end engages the free end of leg 2. When the armature reaches this position, contact 6-43 will be closed and contact 6-45 will be opened. The magnetic field created by winding 7 will then begin to decay, but the decay of this field will be delayed, because winding 7 is on short circuit, and also because of the low reluctance of the magnetic circuit formed by leg 2, back strap 1, leg3, and the left-hand half of armature 5. Winding 8 will then be energized and the growth of the magnetic field due to this Winding, will be comparatively rapid. After an interval of time the torque exerted by the decreasing flux due to winding 7, will be overbalanced by the torque exerted by the flux due to winding 8, and the armature 5 will then swing in counter-clockwise direction until its right-hand end engages the free end of leg 4:. This operation of the armature will reverse the position of contact '6, so that the flux due to winding 8 will begin to decay and winding 7 will become energized. Armature 5' will then again be swung into engagement with the leg 2.

When pole-changer 10 is in the position shown in Fig. 1, the magnetic fluxes due to windings 7 and 8 will be in the directions indicated by the arrows, the flux due to winding 7 being shown by the solid arrows, and that due to winding 8 being shown by the arrows in dash lines. From these arrows it will be observed that when either winding is placed on short circuit, the flux which was due to current in that winding is in the same direction as the flux due to current in the other winding, so that for this reason the decay of flux when either winding becomes deenergized, is still further decayed, This tends to slow down the operation of the armature 5. When the pole' ehanger 10 is in the position shown in Fig. 2, however, it will be observed that when either winding is placed on short circuit, the flux due to the current in that winding is in the opposite direction to the fiuX due to current in the other winding, so that the decay of flux when either winding is placed on short circuit is much more rapid than when the pole-changer is in the position shown in Fig. 1. It follows that the rate of operation of the armature 5.will be increased. In other words, the armature 5 will operate at a relatively low rate when the pole-changer 10 is in the position shown in Fig. l, and at a relatively high rate when this pole-changer is in the position shown in Fig. 2,

Although I have herein shown and described only one form of relay embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. A relay comprising a core having three legs, an armature pivotally attached to the middle leg to swing toward one or the other of the outer legs, a winding on each outer log, a circuit including said windings and a source of current, means operating when said armature is swung toward either outer leg to place the winding on such leg on short circuit, and means for reversing the polarity of the current supplied to one of said windings but not the other whereby the armature will oscillate at one rate or another according to the polarity of the current supplied to said one winding.

2. A relay comprising a pivoted armature, two electromagnets one on each side of the pivotal axis of said armature whereby the armature is swung in one direction or the other according as one magnet or the other is energized, means effective when said armature is swung toward either magnet to place the winding of such magnet on short circuit, and means for reversing the polarity of the current supplied to one of said magnets but not the other whereby the armature will oscillate at one rate or another according to the polarity of the current supplied to said one magnet.

In testimony whereof I afiix my signature.

BENJAMIN MISHELEVICH.

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